Method and terminal for selecting ap

ABSTRACT

There is provided a method for selecting an access point (AP), the method performed by a user equipment. The method may comprise: receiving a prioritized list with respect to APs, the prioritized list includes at least one of roaming consortium information, a network address identifier (NAI), a public land mobile network (PLMN) identifier; scanning at least one or more APs in the vicinity thereby generating an available list which includes at least one or more service set identifiers (SSIDs) and roaming consortium information; acquiring at least one or more NAIs from the roaming consortium information in the available list using pre-stored mapping information; comparing the acquired NAI with the NAI in the prioritized list to select a proper AP.

This application claims the benefit of priority of U.S. Provisionalapplications No. 61/753,939 filed on Jan. 18, 2013, No. 61/767,196 filedon Feb. 20, 2013, No. 61/807,301 filed on Apr. 1, 2013, No. 61/818,916filed on May 3, 2013, No. 61/821,667 filed on May 9, 2013, and No.61/821,725 filed on May 10, 2013, of which are incorporated by referencein their entirety herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method and a terminal for selectingan access point (AP).

Discussion of the Related Art

A 3GPP that establishes a technology standard of a 3^(rd) generationmobile communication system has started a research into long termevolution/system architecture evolution (LTE/SAE) technology as part ofan effort to optimize and improve performance of 3 GPP technologies fromthe end of 2004 in order to cope with various forums and newtechnologies associated with 4^(th) generation mobile communication.

SAE that is progressed around 3GPP SA WG2 is a research into networktechnology to determine a structure of a network with an LTE work of a3GPP TSG RAN and support mobility between model networks and one of keystandardization issues of the 3GPP. This is a work for developing a 3GPPsystem to a system that supports various wireless access technologiesbased on an IP and the work has been progressed for the purpose of anoptimized packet based system that minimizes a transmission delay with afurther improved data transmission capability.

An SAE higher-level reference model defined in the 3GPP SA WG2 includesa non-roaming case and a roaming case of various scenarios, and adetailed content may be referred in TS 23.401 and TS 23.402 which are3GPP standard documents. A network structure diagram of FIG. 1 showsschematic reconfiguration of the SAE higher-level reference model.

FIG. 1 is a Structural Diagram of an Evolved Mobile CommunicationNetwork.

One of largest features of the network structure of FIG. 1 is based on a2 tier model of eNodeB of an evolved UTRAN and a gateway of a corenetwork and although accurately matches each other, the eNodeB 20 hasfunctions of NodeB and RNC of an existing UMTS system and the gatewayhas an SGSN/GGSN function of the existing system.

Another key feature is that a control plane and a user plane between anaccess network and the core network are exchanged to differentinterfaces. In the existing UMTS system, one lu interface exists betweenan RNC and an SGSN, while a mobility management entity (MME) 51 thatundertakes processing of a control signal has a structure separated froma gateway (GW), and as a result, two interfaces of S1-MME and S1-U arerespectively used. The GW includes a serving-gateway (hereinafter,referred to as ‘S-GW’) 52 and a packet data network gateway(hereinafter, referred to as ‘PDN-GW’ or ‘P-GW’) 53.

Meanwhile, in recent years, congestion of a core network of a mobilecommunication provider has been aggravated with an explosive increase ofdata. As a scheme for relieving the aggravated congestion, there is adiscussion intended to offload data of a user terminal to a wirednetwork without passing through a core network of a provider. As aresult of such a discussion, technologies such as IP flow mobility andseamless offload (IFOM), multi access PDN connectivity (MAPCON), etc.for supporting multiple radio access have been proposed. The MAPCONtechnology establishes PDN connections through their preferred radioaccess such as 3GPP access or Wi-Fi access and transmits data throughthe PDN connections. The IFOM technology allows a PDN connection to use3GPP access and Wi-Fi access simultaneously and transmits data throughtheir preferred access.

FIG. 2A is an Exemplary Diagram Illustrating an Example of IFOMTechnology.

Referring to FIG. 2A, the IFOM provides the same PDN connection throughvarious different accesses simultaneously. The IFOM provides offloadingto a seamless WLAN.

Further, the IFOM transfers an IP flow of one same PDN connection fromone access to another access.

FIG. 2B is an Exemplary Diagram Illustrating an Example of MAPCONTechnology.

As known with reference to FIG. 2B, the MAPCON technology easilyconnects IP flows of various PDN connections to other APNs throughdifferent access systems.

According to the MAPCON technology, a UE 10 may create a new PDNconnection on an access which is not previously used. Alternatively, theUE 10 may create a new PDN connection to one selected from variousaccesses which are previously used. Alternatively, the UE 10 maytransfer all or some of all PDN connections which are already connectedto another access.

Technology associated with Wi-Fi interworking includes trafficoffloading technology and technology associated with WLAN selection.That is, technology in which a terminal can automatically select a WLANis standardized (3GPP TS 24.234) and an associated operation isdescribed below. First, the terminal searches neighboring Wi-Fi tocreate a list of available WLANs. This is a list of SSIDs expressing theWLANs. The created list and a preferred WLAN list are compared with eachother to select the most preferred WLAN in the created list. An ANQPquery is transmitted to the selected WLAN to acquire PLMN informationwhich is providable by the WLAN. The most preferred PLMN (for example,Home PLMN) is selected by comparing the acquired PLMN information topreferred PLMN information which is stored in advance and is used toaccess to the corresponding PLMN through an authentication process.

FIG. 3 Illustrates an Environment in which a General AP and a RecentlyDiscussed Hotspot 2.0 AP are Present.

An traditional HotSpot meant that a Wi-Fi service is provided to anunspecific majority in a public place where a floating population islarge. However, with a recent explosive increase in a bandwidth usage,it is difficult to sufficiently provide a bandwidth required as 3^(rd)generation or 4^(th) generation mobile communication technology now. Inparticular, in a commercial area in which a population is dense duringthe daytime, bandwidth management is actually impossible and a HotSpot2.0 that makes a mobile communication network in a population dense areainterwork with a Wi-Fi network to provide a Vertical Handoff service isresearched in order to solve such a problem.

The HotSpot 2.0 as a standard developed in Wi-Fi Alliance (WFA) aims atsimplifying and automating access to a public Wi-Fi network. A mobileterminal aims at recognizing which AP among various neighboring accesspoints is suitable for a usage purpose thereof and authenticating thecorresponding AP from a remote service provider by using appropriatecredentials. To this end, the respective APs is allowed to provide newvarious information, and information indicating whether a specificservice provider is connectable, a HotSpot provider, a roamingconsortium, Venue information (Venue Group, Venue Type), configurationinformation can be provided.

Herein, the roaming consortium is a group of service providers that makea roaming agreement. Numerous service set identifiers (SSIDs) that aremanaged for each roaming consortium may be present according to theroaming consortium and a 3GPP provider who cooperates with the roamingconsortium may not know all of numerous SSIDs. Accordingly, a HotSpot2.0 AP 40 c provides roaming consortium information to increaseefficiency of management instead of the numerous SSIDs.

The roaming consortium information is constituted by a list of a serviceprovider or a company or an agency that made a roaming agreement withthe service provider. Herein, information of each company or agency isexpressed as an organizational unique identifier (OUI). That is, theroaming consortium information is configured in a list form of OUI1,OUI2, . . . , OUI_n. Herein, the OUI can be used by being registered inIEEE, and is information which is unique for each agency. Further, theHotSpot 2.0 AP 40 c may provide BSS load information or bandwidthinformation (for example, WAN Metrics).

Meanwhile, as illustrated, under a situation in which the hotspot 2.0 AP40 c and general APs 40 a and 40 b coexist, the UE 10 receives SSIDinformation from the general APs 40 a and 40 b and the roamingconsortium information from the hotspot 2.0 AP 40 c.

However, since a 3GPP release 11 based UE 10 which has been developed upto now may select only the general APs 40 a and 40 b based on only theSSID and may not read the roaming consortium information, the UE 10 maynot select the hotspot 2.0 AP 40 c.

In detail, the UE 10 provides only SSID information in order to selectthe AP in a 3GPP network in prior art. According to 3GPP release 11, APselection, that is, WLAN selection has been developed aiming atselecting a public land mobile network (PLMN). As a result, the UE 10receives SSIDs broadcasted from the APs 40 a and 40 b to create anavailable list and thereafter, accesses respective APs in order of theSSIDs selected by comparing a preference list stored in advance andinformation on the created list and reads PLMN list informationsupported by the APs. The PLMN information is also compared with apreference PLMN list to select a PLMN having the highest preference.When the PLMN selection is completed, the AP is accessed by using thecorresponding SSID to access the corresponding PLMN.

As described above, since the 3GPP release 11 based UE 10 which has beendeveloped up to now may select only the general APs 40 a and 40 b basedon only the SSID and may not select the hotspot 2.0 AP 40 c.

SUMMARY OF THE INVENTION

The present disclosure has been made in an effort to allow a UE tocorrectly select an AP.

In detail, the present disclosure has been made in an effort to providea scheme that allows a recently developed Hotspot 2.0 to be used even ina 3GPP network system. In particular, the present disclosure has beenmade in an effort to enhance a method for selecting an AP by usinginformation provided by a Hotspot 2.0 AP.

In one aspect, there is provided a method for selecting an access point(AP), the method performed by a user equipment. The method may comprise:receiving a prioritized list with respect to APs, the prioritized listincludes at least one of roaming consortium information, a networkaddress identifier (NAI), a public land mobile network (PLMN)identifier; scanning at least one or more APs in the vicinity therebygenerating an available list which includes at least one or more serviceset identifiers (SSIDs) and roaming consortium information; acquiring atleast one or more NAIs from the roaming consortium information in theavailable list using pre-stored mapping information; comparing theacquired NAI with the NAI in the prioritized list to select a proper AP.

The acquiring of the NAI may include: extracting an organization uniqueidentifier (OUI) from the roaming consortium information in theavailable list; and acquiring an NAI corresponding to the extracted OUIby using the pre-stored mapping information.

The pre-stored mapping information may include an NAI and a PLMN IDcorresponding to an OUI.

The method may further comprise: comparing the PLMN ID acquired from themapping information and the PLMN ID in the preference list with eachother.

The method may further comprise: associating, when an NAI and a PLMN IDwhich match the NAI and the PLMN ID in the preference list are present,a corresponding AP; and performing authentication by using the PLMN ID.

The scanning may include: receiving information on a load and aninstallation place of the corresponding AP through the AP scanning;excluding an AP which does not match a predetermined condition from theavailable list; and filling the AP which matches the predeterminedcondition in the available list.

The predetermined condition may include at least one of a condition forthe load of the AP and a condition for the load for the installationplace of the AP.

an entity in a network providing the preference list is an accessnetwork discovery and selection function (ANDSF).

In one aspect, there is provided a terminal comprising: atransmitting/receiving unit receiving a prioritized list with respect toAPs from an entity in a network, the prioritized list includes at leastone of a roaming consortium information, a network address identifier(NAI), and a public land mobile network (PLMN) identifier; and aprocessor scanning APs in the vicinity thereby generating an availablelist including a service set identifier (SSID) and the roamingconsortium information, acquiring an NAI from the roaming consortiuminformation in the available list, and comparing the acquired NAI withan NAI in the preference list.

According to the present disclosure, a UE that supports a Hotspot 2.0 APcan effectively select an AP. Further, according to the presentdisclosure, a time required to select the AP can be significantlyreduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structural diagram of an evolved mobile communicationnetwork.

FIG. 2A is an exemplary diagram illustrating an example of IFOMtechnology.

FIG. 2B is an exemplary diagram illustrating an example of MAPCONtechnology.

FIG. 3 illustrates an environment in which a general AP and a recentlydiscussed hotspot 2.0 AP are present.

FIGS. 4A and 4B illustrate a network control entity for selecting anaccess network.

FIG. 5 is an exemplary diagram illustrating an environment assumed inthis specification.

FIG. 6 is a flowchart illustrating a scheme according to a firstexemplary embodiment presented in this specification under theenvironment illustrated in FIG. 5.

FIG. 7 is a flowchart illustrating a scheme according to a secondexemplary embodiment presented in this specification under theenvironment illustrated in FIG. 5.

FIG. 8 is a flowchart illustrating a scheme according to a thirdexemplary embodiment presented in this specification under theenvironment illustrated in FIG. 5.

FIG. 9 is a configuration block diagram of a UE 100 and an ANDSF 600according to the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, terms used in the specification will be defined in brief inorder to assist understanding the present invention before a descriptionreferring the accompanying drawings.

UMTS: means a 3^(rd) generation mobile communication network as anabbreviation of a Universal Mobile Telecommunication System

EPS: Means a core network supporting a long term evolution (LTE) networkas an abbreviation of Evolved Packet System. Network evolved from theUMTS

PDN (Public Data Network): An independent network at which a serverproviding a service is positioned

APN (Access Point Name): Provided to UE as a name of an access pointmanaged in the network. That is, the APN indicates a name (string) ofthe PDN. The corresponding PDN for transmitting and receiving data isdecided based on the name of the access point.

NodeB: Installed outdoor as a base station of the UMTS network and acell coverage scale corresponds to a macro cell.

eNodeB: Installed outdoor as a base station of an evolved packet system(EPS) and the cell coverage scale corresponds to the macro cell.

MME: Serves to control each entity in the EPS in order to provide asession for the UE and mobility as an abbreviation of MobilityManagement Entity.

Session: The session is a passage for data transmission and the unitthereof may be PDN, bearer, IP flow unit, or the like. The respectiveunits may be divided into a whole unit (APN or PDN unit) of a targetnetwork, a unit (Bearer unit) divided as a QoS therein, and adestination IP address unit.

PDN connection: Indicates connection from the terminal to the PDN, thatis, association (connection) between the terminal expressed as the IPaddress and the PDN expressed as the APN. The PDN connection meansconnection between entities (terminal—PDN GW) in the core network so asto form the session.

UE Context: UE context information used to manage the UE in the network,that is, context information constituted by a UE id, mobility (presentlocation, and the like), an attribute (QoS, priority, and the like) ofthe session

Service Set ID (SSID): an identifier of a WLAN AP defined in the IEEE802.11

ANDSF (Access Network Discovery and Selection Function): As one networkentity, a policy is provided to discover and select access which theterminal can use by the unit of the provider

Brief Description of Technology Presented in Specification

Meanwhile, hereinafter, schemes presented in the specification will bedescribed below in brief.

First, a 3GPP based access network discovery and selection function(ANDSF) performs a network search function and a data management andcontrol function for providing selective assistance data according to aprovider policy.

The existing ANDSF needs to designate an ID of a WLAN in order to decideaccess preference and the ID may be provided only in a form of a serviceset identifier. However, an ANDSF enhanced according to an embodiment ofthe present invention may provide a preference list defined by usinginformation provided an Hotspot 2.0 AP which has been recentlydeveloped. For example, a preference list is constituted by a networkaddress ID (for example, a network address identifier (NAI) realm) of aprovider or a roaming consortium organizational identifier (OI) inaddition to the SSID. The NAI realm information is address informationof a character string pattern such as attwireless.com. Both informationof the OUI and the NAI realm is different individual information havingdifferent formats, but a service provider may express itself by usingthe two formats due to the common point of expressing service providers.

FIGS. 4A and 4B Illustrate a Network Control Entity for Selecting anAccess Network.

As known with reference to FIG. 4A, the ANDSF may be present in a homepublic land mobile network (hereinafter, ‘HPLMN’) of a UE 100. Further,as known with reference to FIG. 4B, the ANDSF may be present even in avisited public land mobile network (hereinafter, referred to as ‘VPLMN’)of the UE 100. As such, when the ANDSF is positioned on the homenetwork, the ANDSF may be called H-ANDSF 610 and when the ANDSF ispositioned on the visited network, the ANDSF may be called V-ANDSF 620.Hereinafter, the ANDSF 600 is commonly called the H-ANDSF 610 or theV-ANDSF 620.

The ANDSF may respond to a request of the UE to access network discoveryinformation and further, transmit information as necessary even thoughthere is no request from the UE.

The ANDSF may provide information on an inter-system mobility policy,information for discovery of the access network, and information on aninter-system routing, for example, a routing rule.

The information on the routing, for example, the routing rule mayinclude an AccessTechnology, an AccessId, AccessNetworkPriority, and thelike.

Technology called the ANDSF is started as technology that provides apolicy for mobility between heterogeneous network. However, according toa disclosure of the specification, when legacy APs and the Hotspot 2.0APs are present in plural, ANDSF provides information for the UE toselect any AP.

A detailed example will be described with reference to FIG. 5.

FIG. 5 is an Exemplary Diagram Illustrating an Environment Assumed inthis Specification. FIG. 6 is a Flowchart Illustrating a SchemeAccording to a First Exemplary Embodiment Presented in thisSpecification Under the Environment Illustrated in FIG. 5.

As known with reference to FIG. 5, it is assumed that general APs 400 aand 400 b are present and several Hotspot 2.0 APs 400 c, 400 d, and 400e are present.

As illustrated, the general APs 400 a and 400 b broadcast the SSID. Thehotspot 2.0 APs 400 c, 400 d, and 400 e broadcast roaming consortiuminformation as well as SSID. Further, the hotspot APs 400 c, 400 d, and400 e provide information on an access network type regarding whethereach hotspot AP 400 c, 400 d, or 400 e is private, public, free, orpersonal. Further, the hotspot APs 400 c, 400 d, and 400 e may providevenue information. For example, the hotspot APs 400 c, 400 d, and 400 emay provide place type information regarding whether an installationspace is, for example, a school, a hospital, a hotel, an office, a home,or the like.

The hotspot APs 400 c, 400 d, and 400 e are connected with accessnetwork query protocol based servers 800 a, 800 b, and 800 cillustrated, respectively. The ANQP based servers 800 a, 800 b, and 800c provide the NAI realm according to a request.

Hereinafter, information provided through Hotspot 2.0 technology whichis organized will be illustrated in Table 1 below.

TABLE 1 Information provided through Information broadcasted in AP ANQPbased server 1. SSID 1. Roaming Consortium ID list 2. Roaming ConsortiumID 2. NAI Realm list 3. Venue information (Venue Group, Venue Type) 4.BSS Load information

Meanwhile, according to related art, the ANDSF 600 provides only SSIDinformation for selecting an access network, for example, an AP.

However, according to embodiments presented in the specification, theANDSF 600 may provide the preference list using the roaming consortiuminformation or the NAI realm information in addition to the SSID. Thepreference list is illustrated in Table 2.

TABLE 2 PrioritizedAccess  AccessTechnology AccessId SecondaryAccessIdAccessNetworkPriority NAI Realm Roaming Consortium ID

The preference list illustrated in Table 2 above shows preferredaccesses which are arranged. The preferred accesses may include accesstechnology, an access ID, a secondary access ID, an access networkpriority, NAI realm, a roaming consortium ID, and the like. The NAIrealm and the roaming consortium ID may be designated in plural andexpressed according to the priority.

Then, as illustrated in FIG. 6, the UE 100 acquires information fromseveral APs 400 a, 400 b, 400 c, 400 d, and 400 e and compares theinformation with the information in the preference list to select anyone AP.

In detail, if a predetermined AP among several APs 400 a, 400 b, 400 c,400 d, and 400 e is the hotspot 2.0 AP (S110), the UE 100 acquires thebroadcasted SSID and roaming consortium ID (S120).

Subsequently, the UE 100 creates an available list by using the acquiredinformation (for example, the SSID or the roaming consortium ID) (S130).

In addition, the UE 100 compares the SSID or the roaming consortium IDin the available list with the SSID or the roaming consortium ID in thepreference list illustrated in FIG. 6 (S140).

According to a result of the comparison, if the matched SSID is thehighest priority, PLMN information is acquired by accessing thecorresponding AP (S170).

Subsequently, a public land mobile network (PLMN) ID acquired from thecorresponding AP and information of a preferred PLMN list are comparedwith each other (S180).

When the PLMN ID is matched, the PLMN is selected and authentication isperformed (S190).

On the contrary, according to the comparison result (S140), if theroaming consortium ID which is matched has the highest priority, the NAIrealm information is requested and acquired from the ANQP based servers800 a, 800 b, and 800 c of the corresponding AP (S150).

Subsequently, the acquired NAI realm and the NAI realm in the preferencelist are compared with each other (S160).

When the NAI realm is matched, the authentication is performed by usingthe NAI realm (S190).

As described above, under an environment in which the general APs 400 aand 400 b, and the hotspot 2.0 APs 400 c, 400 d, and 400 e coexist,information broadcasted by the respective APs may be different from eachother and the UE 100 may select any one AP according to the preferencelist provided by the ANDSF 600.

However, according to the first embodiment, in order to select andaccess the hotspot 2.0 AP, the NAI realm is queried to the ANQP basedservers 800 a, 800 b, and 800 c and acquired and thereafter, comparedwith the NAI realm in the preference list provided by the ANDSF 600.

However, a time required to query and acquire the NAI realm isrelatively longer than a time required to acquire the SSID. In the worstcase, when the number of hotspot 2.0 APs is considerably large, quite along time may be taken to query and acquire the NAI realm to the ANQPbased servers of all APs.

Meanwhile, the hotspot 2.0 APs 400 c, 400 d, and 400 e provide variousadditional information, the venue information (Venue Group and VenueType), BSS load information, and the like, but according to the firstembodiment, the information may not be used in selecting the AP. Forexample, even though an AP having a large load may be allowed not to beselected when load information is used, the information may not be usedin the first embodiment.

Accordingly, other embodiments capable of solving a disadvantage of thefirst embodiment will be described.

A method according to other embodiments will be summarized below inbrief in order to assist understanding.

As one method, the UE 100 may store the preference list for the SSID orthe roaming consortium ID (OUI) in advance in order to rapidly selectthe AP. As another method, since the NAI realm represents the networkaddress ID of the provider and the OUI in the roaming consortium IDrepresents information on each company or agency, the NAI realm and theOUI have a correspondence relationship. For example of a company in LG,the OUI may be LGI and the NAI realm may be LG.com. Accordingly, whenthe UE 100 stores mapping information indicating the correspondencerelationship in advance and thereafter, receives the preference listfrom the ANDSF server, the NAI realm in the corresponding preferencelist is converted into the OUT according to the mapping information andcompared with the OUI in the roaming consortium broadcasted from thehotspot 2.0 AP to select an AP to be accessed. Subsequently, the PLMN IDis acquired from the accessed AP and a best PLMN or service provider isselected and authenticated.

As another method, the UE 100 stores service provider information (forexample, NAI realm(s) and PLMN ID) which is accessible for each OUI inadvance, rapidly selects the AP by using the stored information, andmoreover, completes even authentication.

FIG. 7 is a Flowchart Illustrating a Scheme According to a SecondExemplary Embodiment Presented in this Specification Under theEnvironment Illustrated in FIG. 5.

First, according to the IEEE 802.11 standard, since the roamingconsortium ID is defined as “each OI (Organizational Identifier)identifies an SSP (Subscription Service Provider) or group of SSPs (i.e,a roaming consortium)” and the OI is expressed as the OUI, the OUI maybe acquired through the roaming consortium ID. Further, for example,since the OUI is expressed as LGI and the NAI realm is expressed asLG.com, the second embodiment enables more rapid AP selection by usingthe correspondence relationship between the NAI realm and the OUI.

That is, according to the second embodiment, an appropriate AP may beselected even without directly using the ANQP query to the AP byappropriately using broadcasted information. First, when an associatedAP fails to access at the time of attempting access by selecting thebest PLMN or service provider, another AP is associated to attemptaccess again by selecting the best PLMN or the service provider.

As such, an AP to be access is selected depending on only thebroadcasted information to increase a probability of acquiring a bestresult within a short time. Further, the NAI realm is not queried andrequested from an ANQP server of an AP not to be actually accessed, andas a result, unnecessary signaling generation may be reduced.

Meanwhile, according to the second embodiment, the ANDSF exemplarilyprovides an enhanced preference list illustrated in Table 3. As knownwith reference to Table 3, the enhanced preference list may include alist (for example, Operator_Controlled_WLAN_Specific_identifier_List)for selecting the AP (that is, the WLAN) and a list (for example,Operator_Controlled_PLMN_Selector_for_WLAN_access_List) for selectingthe PLMN.

Unlike Table 2, in Table 3, the roaming consortium ID is included in thelist for selecting the AP (that is, the WLAN) and the NAI realm isincluded in the list for selecting the PLMN.

TABLE 3 Operator_Controlled_WLAN_Specific_identifier_List  SSID  RoamingConsortium ID  PriorityOperator_Controlled_PLMN_Selector_for_WLAN_access_List  NAI Realm PLMN_ID  Priority

The list (for example,Operator_Controlled_WLAN_Specific_identifier_List) for selecting the AP(that is, the WLAN) is used to select an AP which the UE 100 willassociate. The list for selecting the AP (that is, the WLAN) may includeat least one of the SSID and the roaming consortium ID, and any of themcan take precedence over the other one according to the priority. If thepriority is not designated, the priority may be substituted with anorder disclosed in the list. Alternatively, the NAI realm may bedescribed instead of the roaming consortium ID. In this case, asdescribed above, the mapping information indicating the correspondingrelationship between the OUI and the NAI realm in the roaming consortiuminformation is required. That is, the mapping information may beprovided by a server or stored in a terminal through the provider ornetwork configuration. The mapping information may include the PLMN IDin addition to the correspondence relationship between the OUI and theNAI realm.

Meanwhile, plural PLMN ids and NAI realms may be described in the listfor selecting the PLMN and a priority among the plural PLMN ids and NAIrealms may be decided by the priority. The list is intended to be usedfor selecting the PLMN, but alternatively, may be referred even when theUE 100 creates the available list. That is, the UE 100 mayextract/estimate the roaming consortium ID by using the NAI realminformation of the list for selecting the PLMN and thus, select an AP tobe first associated by using the OUI. In this case, the priorities ofthe list for selecting the AP (that is, the WLAN) and the list areequally used or any one list may be preferentially used. According tothe second embodiment, an overall process is progressed by an order of ascanning process (S210 to S230), an AP selecting process (S240), and aPLMN selecting process (S250 to S270) are progressed in sequence. Eachprocess will be described below.

In the scanning process (S210 to S230), the UE 100 acquires only theSSID in the case of not the Hotspot 2.0 AP but the legacy AP (S215),acquires the SSID and the roaming consortium information (including theOUI) broadcasted from the Hotspot 2.0 AP (S220), and creates theavailable list (S230). For example, an example of the available listcreated when three neighboring hotspot 2.0 APs 400 c, 400 d, and 400 eare searched like the environment illustrated in FIG. 5 is illustratedbelow.

TABLE 4 Ex.) Available WSID list: (SSID2,OUI2), (SSID4, OUI4), (SSID6,OUI6)

Next, when the AP selecting process (S240) is described, the UE 100first compares the information in the available list and informationdefined in the list for selecting the AP (that is, the WLAN) of Table 3for each priority. For example, it is assumed that the list(WLAN_Specific_identifier_List) for selecting the AP (that is, the WLAN)is illustrated as an example in a table below.

TABLE 5 Ex.) WLAN_Specific_identifier_List: (—,OUI1), (—, OUI2), (SSID3,OUI3), (SSID4, —)

Since a part expressed as ‘−’ is not designated, the part is analyzed asany.

When the available list exemplified above and the list for selecting theAP (that is, the WLAN) exemplified above are compared with each other,an AP is selected in order of (−, OUI2) and (SSID4, −).

Next, the PLMN selecting process (S250 to S270) will be described below.

First, the UE 100 converts the roaming consortium information in theavailable list for the selected AP into the NAI realm by using themapping information (S250). As described above, the OUI in the roamingconsortium information may represent the service provider or a groupthereof. That is, since one OUI represents various service providers,one OUI is associated with various service providers. Accordingly, whenthe AP supports a specific OUI, the UE 100 may access a service providernetwork associated with the OUI. In this case, the authenticationprocess (S290) to be described below is performed in order to access theservice provider network, and the NAI realm and the PLMN ID informationacquired through the mapping information may be used in theauthentication process (S290) to be described below. The mappinginformation may be transferred in the network or stored in the terminalin advance in a form of a policy or set-up. A table below illustrates anexample thereof.

TABLE 6 OUI_i = {ServiceProvider_1(NAI_11, NAI_12,PLMN_id_13...),ServiceProvider_2(NAI_21, NAI_22, ...), ... , ServiceProvider_n(NAI_n1,NAI_n2,...)}

Alternatively, when there is no mapping information, the NAI realm andthe PLMN ID may be acquired by querying to the ANQP 800 a, 800 b, or 800c of each AP.

Then, the UE 100 compares the NAI realm acquired from the ANQP 800 a,800 b, or 800 c of each AP with the NAI realm/PLMN ID in the list (forexample, Operator_Controlled_PLMN_Selector_for WLAN_access_List) for theNAI realm in the preference list, that is, the PLMN (S260).

When the NAI realm/PLMN ID is matched, the UE 100 associates the NAIrealm/PLMN ID to the corresponding AP, the UE 100 performsauthentication, for example, AAA authentication (S290). However, whenthe NAI realm/PLMN ID of the corresponding AP does not match the NAIrealm/PLMN ID in the preference list, the aforementioned processes arerepeated with respect to another AP in the available list. Meanwhile,the UE 100 may appropriately modify the NAI by considering the situationof the Home PLMN or the Visited PLMN at the time of performing theauthentication. That is, the UE 100 selects a service provider which ispreferred in the corresponding OUI, and modifies the NAI according tothe PLMN so that the UE accesses to the PLMN.

Meanwhile, when the UE 100 selects the specific AP as described above,the service provider is thereafter selected by comparing the NAI realmand when the same preference is provided, the service provider may beselected by using individual preference lists.

Further, like an OUI_i list illustrated in Table 6 above, severalservice providers may be arranged with respect to one OUI and thepriority may be given to the order. In a general case, if a Homeprovider of the UE 100 is included in the corresponding roamingconsortium, the UE 100 hopes accessing primarily by using the Homeprovider and even in remaining cases, a service provider which ispreferred may be selected according to a roaming agreement. Accordingly,the authentication may be performed according to the correspondingorder. The corresponding home provider may be preferred by using anindicator or a setting value in order to preferentially select the homeprovider.

Further, the OUI_i list is stored based on a record which is succeededafter access through method 1 and thereafter, may be used at the time ofan attempt.

Optionally, the UE 100 may perform authentication by an option below byusing the service provider (NAI realm) acquired through the query to theANQP server 800 a, 800 b, or 800 c by accessing the AP in the order ofthe preference OUI.

A predetermined service provider (NAI realm) among the service providersin the OUI having the highest preference is selected and authenticated.(without a priority list of the service provider)

The service provider having the highest preference is selected among theservice providers in the OUI having the highest preference (the prioritylist of the service provider which is preferred for each OUI is used).

Authentication is performed with the service provider having the highestpriority among the service providers (NAI realms) that receive responsesfrom the ANQP 800 a, 800 b, and 800 c of the APs of all OUIs (a prioritylist of common service providers is used). In this case, Home or thePLMN preferred during roaming may be designated and selected.

According to the second embodiment illustrated in FIG. 7 as above, whenN APs are present therearound, the number of operating times may bereduced as illustrated in Table 7 below.

First, the scanning process is performed similarly to N neighboring APs.

The number of querying times to the ANQP server requires average N/twicebecause the NAI realm information or the PLMN information is acquired byarbitrary visitation in the case of the method by the first embodiment.However, according to the second embodiment, the access is performed byconsidering the priority in the OUI information acquired from thebroadcasted roaming consortium ID. In this case, when a correlationbetween the OUI in the mapping information and the NAI realm or the PLMNis high (that is, when the correlation is 1), the access is performedonly once. When the correlation is low, since the method is the same asthe existing method even in the worst case, the access may be performedat N/twice. The average number is set as N/4, but when the availablelist is substantially searched, it is possible that the successfulaccess can be achieved with one or two times of trial.

TABLE 7 Full search Present invention # of Scanning N N # of ANQP (whenN/2 N/2 OUI/Realm, PLMN id has no correlation) # of ANQP (when OUI/ N/21 Realm, PLMN id has a strong correlation) # of ANQP (an N/2 N/4 averageof two above cases)

FIG. 8 is a flowchart illustrating a scheme according to a thirdexemplary embodiment presented in this specification under theenvironment illustrated in FIG. 5.

In the third embodiment, an AP selection is enhanced by using stateinformation. As described above, the Hotspot 2.0 APs 400 a, 400 c, and400 e broadcast various information indicating a state or a feature ofthe AP, for example, venue information (Venue Group and Venue Type), BSSload information and the like. Therefore, according to the thirdembodiment, the UE 100 considers broadcasted additional information andwhen the additional information does not match a predeterminedcondition, the UE 100 excludes the APs from the available list. Thepredetermined condition may be expressed as follows.

TABLE 8 Venue Type:any BSS Load < 70

In detail, referring to FIG. 8, the UE 100 acquires various informationindicating the state or feature from the hotspot 2.0 APs 400 a, 400 c,and 400 e, for example, the venue information (Venue Group and VenueType), the BSS load information, and the like in addition to the SSIDand the roaming consortium information according to the thirdembodiment.

In addition, the UE 100 excludes the AP that does not match thepredetermined condition while creating the available list (S330). Assuch, the available list may be more simplified by excluding the APwhich does not match the condition.

Meanwhile, when the load information is used among the aforementionedvarious additional information, the UE 100 may select a less-loaded AP.When there is no less-loaded AP, another radio access technology (RAT)may be alternatively selected.

Since other processes illustrated in FIG. 8 are similar as the processesof FIG. 7, a detailed description thereof will be omitted.

Contents which have been described up to now will be organized as below.

The present specification addresses the key issue of “Support WLANaccess through roaming agreements. However, it is applicable also toscenarios where WLAN access is provided without roaming agreements.

The present specification proposes to extend the ANDSF selectionpolicies to support also selection policies based on the Realms and/orthe Organizational Unique Identifiers (OUIs) which are supported byHotspot 2.0 compliant WLAN networks. The ANDSF may send policies to UEbased on Realms and/or OUIs to indicate for example that “WLANs thatinterwork with Realm=PartnerX.com have the highest access priority”. TheUE uses the Realms and/or OUIs as an alternative way (instead of usingSSID) to identify and prioritize the discovered WLAN access networks.

A Hotspot 2.0 compliant UE is capable to discover the Realms and/or OUIssupported by a specific WLAN access network prior to association byusing the applicable discovery procedures (e.g. based on the ANQPprotocol) and/or by receiving the beacon transmissions of APs (some OUIsare included in the AP beacon messages).

Roaming consortium OI is an identifier representing an SSP (Subscriptionservice provider) or group of SSPs. One or more service providers can bemembers of one roaming consortium OI. When a WLAN AP is selected basedon roaming consortium OI, a preferred service provider should be derivedfrom the roaming consortium. Therefore, the ANDSF MO is enhanced so thata roaming consortium OI has a list of preferred 3GPP service providers(e.g. realms) including Home PLMN. This list is used by the UE to selecta preferred service provider which is related to the preferred roamingconsortium. That is, once a preferred roaming consortium is selected, apreferred service provider is selected from the members of the preferredroaming consortium. This can be done by comparing the service providerscaptured from the WLAN AP and the preferred service provider list of theroaming consortium OI. If a service provider is selected, the UE (i)constructs a NAI (e.g. decorated NAI for VPLMN) when it attempts EAP-AKAauthentication over a selected WLAN access network.

This allows a UE to select the preferred 3GPP service provider toauthenticate with upon selecting WLAN based, among other information, onthe list of roaming consortium that the UE may discover from the WLANAP, e.g. by means of HS2.0 ANQP query or beacon message if the AP isHS2.0 capable.

The methods described above may be implemented by hardware. Theimplementation of the hardware will be described with reference to FIG.9.

FIG. 9 is a Configuration Block Diagram of a UE 100 and an ANDSF 600According to the Present Disclosure.

As illustrated in FIG. 9, the UE 100 includes a storage means 101, acontroller 102, and a transmitting/receiving unit 103. In addition, theANDSF 600 includes a storage means 601, a controller 602, and atransmitting/receiving unit 603.

The storage means 101 and 601 stores the aforementioned methods.

The controllers 102 and 112 control the storage means 101 and 601 andthe transmitting/receiving units 103 and 603. In detail, the controllers102 and 602 execute the methods stored in the storage means 101 and 601.In addition, the controllers 102 and 602 transmit the aforementionedsignals through the transmitting/receiving units 103 and 603.

Although preferable embodiments of the present invention has beenexemplarily described as above, the scope of the present invention islimited to only the specific embodiments, and as a result, variousmodifications, changes, or enhancements of the present invention can bemade within the spirit of the present invention and the scope disclosedin the appended claims.

1-15. (canceled)
 16. A method for selecting an access point (AP), themethod performed by a user equipment and comprising: scanning at leastone or more APs in the vicinity; generating an available list includingat least one or more of a service set identifiers (SSID) and roamingconsortium information, which are acquired from the scanning, wherein,if an any AP searched from the scanning corresponds to a hotspot 2.0based AP, the available list includes both of the SSID and the roamingconsortium information; acquiring at least one or more network addressidentifiers (NAIs) from the roaming consortium information included inthe available list based on pre-stored mapping information; andselecting an any AP, based on a comparison of the at least one or moreacquired NAI with at least one or more NAIs in a prioritized list withrespect to APs.
 17. The method of claim 16, further comprising receivingthe prioritized list with respect to APs, the prioritized list includingat least one of: roaming consortium information, the at least one ormore NAIs, and a public land mobile network (PLMN) identifier.
 18. Themethod of claim 17, wherein the acquiring of the NAI includes:extracting an organization unique identifier (OUI) from the roamingconsortium information included in the available list; and acquiring anNAI corresponding to the extracted OUI based on the pre-stored mappinginformation.
 19. The method of claim 18, wherein the pre-stored mappinginformation includes an NAI and a PLMN ID corresponding to an OUI. 20.The method of claim 19, further comprising comparing the PLMN IDacquired from the pre-stored mapping information and the PLMN ID in theprioritized list with each other.
 21. The method of claim 20, furthercomprising: performing an association to a corresponding AP, when an NAIand a PLMN ID which match the NAI and the PLMN ID in the prioritizedlist are present; and performing authentication by using the PLMN ID.22. The method of claim 16, wherein the scanning includes: acquiringinformation on a load and an installation place of the at least one ormore APs; excluding any AP which does not match a predeterminedcondition from the available list; and adding any AP which matches thepredetermined condition into the available list.
 23. The method of claim22, wherein the predetermined condition includes at least one of: acondition for the load of the AP and a condition for the load for theinstallation place of the AP.
 24. The method of claim 17, wherein theprioritized list is received from an access network discovery andselection function (ANDSF).
 25. A terminal, comprising: a transceiver;and processor configured to: scan at least one or more APs in thevicinity; generate an available list including at least one or more of aservice set identifiers (SSID) and roaming consortium information, whichare acquired from the scanning, wherein, if an any AP searched from thescanning corresponds to a hotspot 2.0 based AP, the available listincludes both of the SSID and the roaming consortium information;acquire at least one or more network address identifiers (NAIs) from theroaming consortium information included in the available list based onpre-stored mapping information; and select an any AP, based on acomparison of the at least one or more acquired NAI with at least one ormore NAIs in a prioritized list with respect to APs.
 26. The terminal ofclaim 25, wherein the processor is further configured to receive theprioritized list with respect to APs, the prioritized list includes atleast one of roaming consortium information, the at least one or moreNAIs, and a public land mobile network (PLMN) identifier.
 27. Theterminal of claim 26, wherein the acquiring of the processor includes:extracting an organizational unique identifier (OUI) from the roamingconsortium information in the available list; and acquiring an NAIcorresponding to the extracted OUI by using the pre-stored mappinginformation.
 28. The terminal of claim 27, wherein the pre-storedmapping information includes an NAI and a PLMN ID corresponding to anOUI.
 29. The terminal of claim 28, wherein the processor is furtherconfigured to compare the PLMN ID acquired from the mapping informationand the PLMN ID in the prioritized list with each other.
 30. Theterminal of claim 29, wherein the processor is further configured to:perform an association to a corresponding AP when an NAI and a PLMN IDwhich match the NAI and the PLMN ID in the prioritized list are present;and perform authentication by using the PLMN ID.
 31. The terminal ofclaim 25, wherein the scanning of the processor includes: acquiringinformation on a load and an installation place of the at least one ormore APs; excluding any AP which does not match a predeterminedcondition from the available list; and adding any AP which matches thepredetermined condition into the available list.
 32. The terminal ofclaim 31, wherein the predetermined condition includes at least one of:a condition for the load of the AP and a condition for the load for theinstallation place of the AP.